Method and apparatus for cryosurgery



' May 19, 1970 RECRUMPETA; 3,512,531 METHOD AND APPARATUS FORCRYOSURGERY Y I 3 Sheets-Sheet 1 Filed Jan. 11, 1968 INVENTORJ May 19,1970 R'. E. CRUMP ET AL- METHOD AND APPARATUS FOR CRYOSURGERY File dJan. 11, 1968 3 Sheets-Sheet 2 R. E. CRUMP ET AL METHOD AND APPARATUSFOR CRYOSURGERY May 19, 1970 Filed Jan. 11, 1968 3 Sheets-Sheet 5 UnitedStates Patent 01 iice 3,512,531 Patented May 19, 1970 3,512,531 METHODAND APPARATUS FOR CRYOSURGERY Ralph E. Crump, Trumbull, and Frank L.Reynolds,

Monroe, Comm, assignors to Frigitronics, Inc., Bridgeport, Conn., acorporation of Connecticut Filed Jan. 11, 1968, Ser. No. 697,177 Int.Cl. A61b 17/36 US. Cl. 128-3031 12 Claims ABSTRACT OF THE DISCLOSURE Amethod and apparatus for performing a cryosurgical endarterectomy. Acryosurgical instrument has an elongated probe designed to operate belowthe freezing point along one side, the opposite side remainingrelatively Warm. The probe is inserted into the artery and positioned inthe demarcation between the adventitia and the diseased intima with itscold side in contact with the intima. The probe is then caused to cooland adhere to the intima. The probe and attached intima are thenwithdrawn from the artery.

BACKGROUND OF THE INVENTION Atherosclerosis is recognized as a majormedical problem. This condition arises when a coating of fattysubstances such as cholesterol deposits on or in the intima(endothelial) layer of an artery. This creates a constriction leading toserious and often fatal results. The current state of the medical art issuch that blood cholesterol levels can be measured and some arterialrestrictions can be diagnosed and physically located. Furthermore, atechnique has recently been devised for removing the diseased intima.

The new surgical technique is known as gas endarterectomy and is foundedon the fact that a zone of demarcation usually exits between the intima,with its deposit of cholesterol or calcified cholesterol, and theadventitia. In the gas endarterectomy procedure, a bolus of carbondioxide is injected under pressure into the artery between theadventitia and the diseased intima. This pressurized gas acts as adissecting medium and separates the intima from the adventitia. Afterhis initial separation, the arterial section bein gtretaed is partiallyopened by longitudinal incisions and a gas spatula is employed tocomplete the separation. The inner core is then transected at its twoends and removed by means of an elongated clamp which is passed down thedissected plane of the blood vessel to grasp and withdraw the core. Thearterial incisions are then closed in the usual manner.

The technique described above promises to be of substantialimportanceparticularly in more advanced cases of atherosclerosis.However, the technique has one serious weakness. This is the finalremoval of the diseased intima. The intima has a somewhat softconsistency so that complete removal by means of a clamp or forceps isdifficult. This is especially true in the treatment of long arteries,such as found in the legs, where a core of as much as twenty-four inchesmay be removed. If any residue of the intima remains in the artery, itmay form the nucleus of a clot leading to thrombosis or stroke.

Accordingly, it is a primary object of the present invention to providean improved method for removing the diseased intima of a blood vesselafter dissection.

Other objects are to provide such a method which removes all thedissected intima; to provide an apparatus for practicing such method andto provide such an apparatus which operates upon the principle ofcryoadhesion.

SUMMARY OF THE INVENTION The present invention is based upon theprinciple of cryoadhesion, or the adhesion of moist tissue to an objectcooled well below freezing temperature. Cryoadhesion in and of itself isnot new but has been used in other surgical procedures, such as cataractremoval. For example, in US. Pat. 3,289,749 of Ralph E. Crump, there isdisclosed a probe for such an application which is thermoelectricallycooled. Experience with that probe by a number of ophthalmologists hasillustrated that cold metallic surfaces will adhere to warm moist tissuesurfaces with sufficient adhesion to manipulate the tissue. Inaccordance with the present invention, there is provided a long, thin,and relatively flexible probe for insertion between the adventitia andintima of a length of artery. The probe is designed to be cooled alongone side of .its elongated surface to adhere to the loosened intimawhile the opposite surface remains nonadherent with respect to theadventitia. Controls are provided to permit the probe to be inserted inits warm state and thereafter cooled. When adherence to the intima iscomplete, the probe is withdrawn, bringing with it the diseased portionof the intima.

BRIEF DESCRIPTION OF THE DRAWINGS An understanding of this invention maybe best achieved by reference to the figures of the attached drawingswherein:

FIG. 1 is a perspective view of a cryosurgical instrument in accordancewith this invention;

FIG. 2 is a vertical cross section of the instrument of FIG. 1;

FIG. 3 is a cross section taken substantially along the line 3-3 of FIG.2;

FIG. 4 is an enlarged vertical section of the end of the probe portionof this invention;

FIG. 5 is a cross section taken substantially along the line 5-5 of FIG.4;

FIG. 6 is a cross section taken substantially along the line 6-6 of FIG.4;

FIG. 7 is an enlarged cross section taken substantially along the line7-7 of FIG. 2;

FIG. 8 is a cross section taken substantially along the line 8-8 of FIG.2;

I FIG. 9 is a view similar to FIG. 8 illustrating one step in theoperation of the mechanism of the invention;

FIG. 10 is a view similar to FIG. 9 illustrating a further step in theoperation of the mechanism of the invention; and

FIGS. 11-14 illustrate steps in a surgical procedure utilizing theapparatus of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT With particular reference toFIG. 1, there is illustrated a cryosurgical instrument in accordancewith this invention comprising a handle 10, an elongated probe 12, acontrol lever 14, a refrigerant inlet line 16, a refrigerant outlet line18 and a carbon dioxide supply line 20.

Referring now to FIG. 2, the basic structural framework of the mechanismof this invention will be seen to comprise a chassis member 22 formedessentially of strap metal and including a widened front plate 24 and acircular rear plate 26. The front plate 24 is drilled to receive thereduced diameter ends of an inlet valve body 28 (FIG. 8) and an exhaustvalve body 30. The construction of these valve bodies will he mostapparent from FIG. 8 wherein it will be seen that the inlet valve body28 includes an axial passageway 32 over most of its length which, at itsforward end, is necked down to form a reduced diameter outlet 34. Atapered valve seat 36 is thus formed between passageway 32 and outlet34.

The exhaust valve body 30 has essentially the same externalconfiguration as inlet valve body 28. However, it is provided with anenlarged internally threaded opening 38 at its forward end and a smallerdiameter passage 40 3 along its rearward length. A conical valve seat 42is formed between opening 38 and passage 40. A threaded plug 44 ispositioned in opening 38 and defines a fluid passage 46 terminating at atransverse slot 48 across the rear face of plug 44.

A resilient metallic inlet bellows 50 is mounted on the inlet valve body28 and a similar exhaust bellows 52 is mounted on the exhaust valve body30. A support block 54 is mounted on the rearward end of the inletbellows 50 and supports the end of an elongated valve core 56. Thismechanical support is achieved by means of a threaded plug 58 in the endof support block 54 which screws downward against the enlarged head 60of the valve core 56. Valve core 56 extends forwardly through thebellows and into passageway 32. The valve core includes a conicallytapered forward end 62 positioned within the valve seat 36. Forward end62 defines along its tapered surface a narrow bleed slot 64. Extendingrearwardly from plug 58 is threaded screw 66 which carries an internallythreaded tubular stop member 68 positioned to engage rear plate 26. Alsomounted on screw 66, but near plug 58, is a control nut 70.

Mounted on the end of exhaust bellows 52 is a support block 72 whichdefines a cylindrical recess 74 and an axial passage 76 communicatingtherewith. An exhaust valve stem 78 extends through passages 40 and 76and is threaded along its rearward portion to carry a cylindricalactuator 80 which is mounted within recess 74 and a control nut 82. Theforward end of the exhaust valve stem 78 is enlarged to define a conicalvalve face 84 arranged to seat within valve seat 42 and a cylindricalhead 86 having a transverse slot 88;

A rectangular floating bar 90 includes a pair of openings which looselyengage screw 66 and exhaust valve stem 78 and bears against control nuts70 and 82. The t control lever 14 is substantially L-shaped, as shown inFIG. 2 and is mounted in a pivot opening 92 in chassis member 22 withits short vertical leg extending downwardly and against the floating bar90. The rear plate 26 is provided with a L-shaped slot 94 through whichcontrol lever 14 extends as shown in FIG. 3, the slot being furtherprovided with a projection 96 for retaining the control member 14 in adepressed position.

The refrigerant inlet line 16 is connected through a suitable coupling16a to a delivery tube 1619 which communicates with passage 32 in inletvalve body 28. The refrigerant exhaust line 18 is similarly connectedthrough coupling 18a to exhaust tube 18b which communicates with passage40 in exhaust valve body 30.

The valve mechanism contained in handle is enclosed by a tubular sheath98 which, in turn, is closed at its forward end by a shaped finger piece100. Finger piece 100 defines an axial opening 102 which carries aplastic sleeve 104.

The probe 12 portion of the instrument extends outwardly from theplastic sleeve 104 and includes a delivery tube 106 having one endconnected in outlet 34 of inlet valve body 28 and a return tube 108communicating with fluid passage 46 in plug 44. Fluid communicationbetween the two remote ends of delivery tube 106 and return tube 108 isprovided by a small hollow metallic tip member 110. The tip member 110includes a tab 112- which extends rearwardly from the forward end of tipmember 110 and in spaced relationship to tubes 106 and 108. Extendingalong the entire length of tubes 106 and 108 is a plastic insulator tube114, molded to fit tubes 106 and 108 and bonded directly thereto, whichdefines a gas passage 116. The forward end of the plastic insulator tube114 is securely retained in position on the probe by means of tab 112which extends within gas passage 116 as shown in FIGS. 4 and 6. A carbondioxide delivery tube 118 extends through handle 10 from the carbondioxide supply line 20 and fitting 20a to insulator tube 114.

The operation of the mechanical features of the invention may be bestunderstood by reference to FIGS. 8-10.

In considering the operation, it is to be understood that therefrigerant inlet line 16 is connected to inject refrigerant into thepassageway 32 of the inlet valve body 28 while the refrigerant exhaustline 18 is connected to passage 40 of exhaust valve body 30. Theopposite end of refrigerant exhaust line 18 may either vent toatmosphere or into a vacuum pump. It is also to be understood that theapparatus described herein will operate with a number of differentfluids such as liquid nitrogen, precooled gases and liquids, and gasessuch as CO utilizing the Joule-Thompson effect. However, for purposes ofthis discussion, it will be assumed that a vaporizing liquid refrigerantis to be employed such as dichlorodifluoromethane,chlorodifluoromethane, bromotrifluoromethane, or mixtures thereof.

At the beginning of the operating cycle, which is illustrated in FIG. 8,the control lever 14 is in its uppermost position as illustrated in FIG.3. The forward end 62 of valve core 56 is displaced from valve seat 36.This positive open position is maintained by the pressurized liquidrefrigerant which fills the entire inlet bellows 50, the delivery tube106, and the return tube 108 as well as the opening 38 in exhaust valvebody 30. However, the liquid does not pass beyond opening 38 due to thefact that valve face 84 is seated tightly against valve seat 42. Thisresults from the fact that exhaust bellows 52 is somewhat compressed andits normal resiliency forces actuator 80 toward the rear which, in turnretracts the exhaust valve stem 78. Thus, in the condition illustratedin FIG. 8 the probe 12, comprising delivery tube 106 and return tube108, is warm due to its being completely filled with a relatively warmliquid. It will also be noted that excessive travel of valve core 56 isprevented by means of stop member 68 which abuts against the rear plate26.

As actuation of the mechanism is begun, control lever 14 is depressed toposition 14a illustrated in FIG. 3. It will be noted that the floatingbar 90 is only loosely positioned over screw 66 and exhaust valve stem78. It will also be recalled that inlet bellows is filled withpressurized liquid. Accordingly, the first step in the actuation,

, as illustrated in FIG. 9, is a cocking of floating bar 90 which forcescontrol nut 82 and exhaust valve stem 78 forwardly against the lesserresistance of bellows 52. This moves valve face 84 away from valve seat42, opening the system to exhaust. The inlet valve comprising valve seat36 and the forward end 62 of valve core 56 remains open. This permits aflow of liquid refrigerant to pass through the delivery tube 106 and thereturn tube 108, thus clearing the system of any gas pockets oraccumulations of moisture or oil Which might interfere with itsoperation. This also provides a warming position for rapid thawing ifthe probe has previously been refrigerated.

The final step is the full depression of control lever 14 into its stopposition as illustrated 'by 14b of FIG. 3 In going from position 140: toposition 14b, two things occur in sequence. First, the oulet bellows 52is compressed even further and head 86 of exhaust valve stem 78 iscaused to seat against the end of plug 44. This limits further travel ofexhaust valve stem 78. Accordingly, further movement of floating bar islimited to compression of inlet bellows 50 by actuation of screw 66 tothe position illustrated in FIG. 10. In this position, the forward end62 of valve core 56 is seated firmly against valve seat 36. This wouldnormally close the inlet valve but bleed slot 64 provides a meteringpassage for a small amount of liquid refrigerant which is forced throughunder pressure. The liquid refrigerant expands as it enters deliverytube 106 and vaporization continues throughout the length of deliverytube 106 and return tube 108, thus causing cooling of these tubes totemperatures well below freezing.

As the purpose of the instrument described herein is to adhere to thediseased intima, but not to the adventitia, it is important that oneside of the probe be insulated to prevent adherence to the arterialwall. This is accomplished in the disclosed embodiment by means of aplastic insulator tube 114 which extends along the entire length of oneside of probe 12. This tube is molded to fit the tubes 106, 108 and isbonded directly to them. The plastic material of the tube should be of atype which presents a smooth surface creating little or no adhesion ordrag on adjacent tissue. Such materials may be, for example,polyvinylchloride, polytetrafluouroethylene or rubber materials such asurethane or silicone. Furthermore, this tube defines a gas passage 116,through which carbon dioxide from the carbon dioxide supply line 20 maybe introduced. This gas performs two functions, first, it serves as athermal insulating medium, secondly, in is suing from the end of theprobe, it helps to separate the intima from the adventitia and therebyfacilitates entry of the probe 12 into the diseased vessel.

Although it will be understood that the size and resiliency of the probemay be varied to suit the expected conditions, some values will be givento facilitate an understanding of the invention. For example, the lengthof the probe 12 may be from approximately four to twenty-four inches.The width, as viewed, for example in FIG. 7, may be from to 4 inch. Thevertical thickness, as similarly viewed, may be from to A2 inch. Thetubes 106, 108 may be of any suitable material, such as stainless steel.

An endarterectomy employing the method and apparatus of this inventionis illustrated in FIGS. 11-14. In FIG. 11, the artery A selected fortreatment is first isolated by means of suitable vascular clamps C. Thegas needle N is then inserted tangentially into the arterial wall andcarbon dioxide gas is introduced between the adventitia and the diseasedintima. As the gas expands along the arterial section, it forces apartthe intima and the adventitia. A longitudinal incision I is then made atone or both ends of the arterial section and a gas spatula S is Workedalong the plane of separation between the adventitia and the intima tofully complete the separation. The gas spatula is aided in this task bymeans of carbon dioxide gas which passes through its handle and outthrough suitable openings in the forward end of the spatula. Thediseased intima is now severed at each end of the arterial sectionunless both ends of the diseased portion are encompassed within thelength of probe 12, and it can be removed complete. Thereafter, theprobe 12 is inserted into the artery, along the plane of dissection,while the probe is in its warm condition. During insertion, carbondioxide gas may be expelled from gas passage 116 to achieve a gentleseparation of the intima from the adventitia. Other suitable fluids maybe used for this purpose. The probe is inserted as shown in FIG. 13 insuch a manner that the exposed metallic surfaces of delivery tube 106and return tube 108 are in contact with the intima, while the adventitiais contacted only by the insulator tube 114. After complete insertion ofprobe 12, the control lever 14 is depressed and locked into its freezingposition. Cooling of the probe begins immediately as disclosed above andsoon forms a cryoadhesion to the intima. The probe is then carefullywithdrawn, as shown in FIG. 14-, bringing with it the entire dissectedportion of the intima. If a change of position of the probe is required,it may be easily thawed by releasing lever 14 to fill the probe withliquid Freon. After repositioning, the lever 14 may be depressed onceagain to achieve freezing. After extraction, the incisions I are closedin a standard fashion.

It will be understood by those skilled in the art that a number ofvariations and modifications may be made in this invention withoutdeparting from its spirit and scope. For example, instead of the handheld and hand actuated valving mechanism illustrated herein, a remotesystem may be employed whereby purging, freezing and defrosting may becontrolled by someone other than the surgeon, for example, by means ofmechanically, hydraulically, or electrically operated controls in theprobe handle. Many other variations and modifications will also beapparent to those skilled in the art. For example,

the probe made he designed with an insulating sleeve along its entirelength, leaving only the tip exposed for removal of clots and smallblockages. Also, other structural modifications, such as a U bend inplace of tip member 110 and differently shaped and positioned tubes andinsulators may be employed. Accordingly, the foregoing description is tobe construed as illustrative only, rather than limiting. This inventionis limited only by the scope of the following claims.

What is claimed is:

1. In the method of performing an endarterectomy wherein a length ofartery to be treated is isolated, an incision is made through theadventitia, and the itima is separated from the adventitia along saidlength of artery, the improvement which comprises: inserting into saidartery, between said adventitia and itima, an elongated probe having afirst surface in contact with said intima and a second surface incontact with said adventitia; cooling said first surface to form anadhesion between said first surface and said intima; removing said probeand adhering intima from said artery; and closing said arterialincision.

2. The method of claim 1 wherein said first surface comprises arefrigerated member and said second surface comprises a thermalinsulating member.

3. The method of claim 2 wherein said refrigerated member comprises apair of refrigerant-containing tubes.

4. The method of claim 2 wherein said thermal insulating membercomprises a tube defining a fluid passage therethrough.

5. Cryosurgical apparatus which comprises: elongated flattened probemeans having spaced first and second elongated surfaces; a delivery tubeand a return tube in parallel relationship to define said first surface;fluid passage forming means at the tip of said probe interconnectingsaid delivery and return tubes; means for injecting a fluid refrigerantinto said delivery tube to cool said first surface; means for exhaustingsaid fluid refrigerant from said return tube; and thermal insulationmeans secured to said delivery and return tubes and forming said secondsurface.

6. Cryosurgical apparatus which comprises: elongated probe means havingspaced first and second surfaces; means for injecting a fluidrefrigerant into said probe means to cool said first surface comprisingan inlet valve having an open position and a closed position and meansforming a fluid bypass passage around said valve when in its closedposition; means for exhausting said fluid refrigerant from said probemeans; and thermal insulation means covering said second surface.

1 fining a bleed slot therein.

8. The apparatus of claim 6 wherein said exhausting means comprises anexhaust valve having an open and closed position.

9. The apparatus of claim 8 wherein said inlet valve is normally openand said exhaust valve is normally closed.

10. The apparatus of claim 9 further including means for opening saidexhaust valve and thereafter closing said inlet valve.

11. The apparatus of claim 5 wherein said thermal insulation meanscomprises a tube defining a passage therethrough having an outlet at theend of said probe means.

12. The apparatus of claim 11 further including means for injecting agas into said passage.

References Cited UNITED STATES PATENTS 3,228,400 1/1966 Armao 128303.13,289,424 12/1966 Shepherd. 3,298,371 1/1967 Lee 128-303.].

LAWRENCE W. TRAPP, Primary Examiner

